Circulating matrix Gla protein: a potential tool to identify minor carotid stenosis with calcification in a risk population.

Background: Carotid calcification is an independent marker for future ischemic events, which are more frequently encountered in postmenopausal women as the prevalence of type 2 diabetes mellitus (T2DM) and hypertension (HT) increases. Matrix Gla protein (MGP) is a major inhibitor of vascular calcification. Here, we report on the prospect of serum MGP to become an identifying tool for minor carotid stenosis (minCAS) with calcification in a risk population.

Methods: Based on carotid ultrasound examination, out of 72 enrolled postmenopausal women, 33 had minCAS with carotid calcification (minCAS group) and 39 were without minCAS and carotid calcification (non-minCAS group). Serum total MGP, high-sensitivity C-reactive protein (hs-CRP), bone mineral density (BMD) and carotid intima-media thickness (CIMT) were determined.

Results: We found significantly elevated serum MGP levels in the minCAS compared to the non-minCAS group (p < 0.05). MGP was independently associated with hs-CRP (unstandardized β -regression coefficient = 2.6; 95 % CI 0.007 – 5.3; p = 0.049) and CIMT ( β = – 611.3; 95 % CI – 1172.6 – – 49.9; p = 0.034) within the minCAS group, but not with BMD. Furthermore, significantly higher MGP levels were determined in two minCAS subgroups (one with HT or T2DM and second with both diseases) compared to a non-minCAS subgroup with HT or T2DM (p < 0.05 and p < 0.01, respectively). A threshold of 87.9 μ g/L serum MGP (area under the receiver operating characteristic = 0.72 } 0.06; 95 % CI 0.60 – 0.84; p = 0.001) may identify minCAS with calcification in postmenopausal women with 63 % precision.

Conclusions: Higher circulating MGP levels could help identify minCAS with calcification in a relatively homogenous risk population (i.e., postmenopausal women), regardless of underlying cardiovascular risk factors.